Internet Of Smells: Giving A Machine The Job Of Sniffing Out Spoiled Food

May 31, 2018 by 17 Comments

Has the food in your pantry turned? Sometimes it’s the sickening smell of rot that tells you there’s something amiss. But is there a way to catch this before it makes life unpleasant? If only there were machines that could smell spoiled food before it stinks up the whole place.

In early May, I was lucky enough to attend the fourth FabLab Asia Network Conference (Fan4). The theme of their event this year was ‘Co-Create a Better World’. One of the major features of the conference was that there were a number of projects featured, often from rural areas, that were requesting assistance throughout the course of the conference.

Overall there were many bright people tackling difficult problems with limited resources. This is how I met [Yogesh Kulkarni] who runs a FabLab in Pabal, a farming community not far from Pune, India. [Yogesh] has also appeared on TED Talks (video here). He explained to me that in his area, vendors sell milk-based desserts. These are not exactly refrigerated, and sometimes people become ill from eating them. It would be nice if there was a way for the vendors to avoid selling the occasional harmful product.

I’ve had similar concerns with food safety in my area (Vietnam), and while it has been fine nearly all of the time, a few years ago I nearly died from a preventable food-borne illness. I had sufficient motivation to do a little research.

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Accurate Coffee Billing Through Reverse Engineering

May 31, 2018 by 37 Comments

If you’ve ever worked in a stingy office, you’ve become familiar with the communal coffee maker that runs on some variant of the honor system. There’s bits of paper, a coin jar shabbily sealed with sticky tape, and the routine note every six months telling people off for not paying for their daily brew. It all gets a bit much. Thankfully, if you work with [Fabian], it’s no longer a problem (PDF link).

The project forms the basis for [Fabian]’s thesis, in which a DeLonghi coffee maker is reverse engineered. This is undertaken with the explicit goal of properly metering the amount of consumables (coffee beans) used per beverage, to more fairly charge users depending on their brew of choice. This involves breaking down and understanding the coffee maker’s internal communications, as well as implementing a system to record and handle billing. For reasons of simplicity, [Fabian] decided that this should be handled using his colleague’s existing computer accounts. Easy!

It’s a highly academic approach to what we’re sure was a very stimulating project with lots of delicious aromas. Coffee’s a popular topic among hackers, that’s for sure – check out this roaster to take your game to the next level.

 

Serial Connection Over Audio: Arduino Can Listen To UART

May 31, 2018 by 19 Comments

We’ve all been there: after assessing a problem and thinking about a solution, we immediately rush to pursue the first that comes to mind, only to later find that there was a vastly simpler alternative. Thankfully, developing an obscure solution, though sometimes frustrating at the time, does tend to make a good Hackaday post. This time it was [David Wehr] and AudioSerial: a simple way of outputting raw serial data over the audio port of an Android phone. Though [David] could have easily used USB OTG for this project, many microcontrollers don’t have the USB-to-TTL capabilities of his Arduino – so this wasn’t entirely in vain.

At first, it seemed like a simple task: any respectable phone’s DAC should have a sample rate of at least 44.1kHz. [David] used Oboe, a high performance C++ library for Android audio apps, to create the required waveform. The 8-bit data chunks he sent can only make up 256 unique messages, so he pre-generated them. However, the DAC tried to be clever and do some interpolation with the signal – great for audio, not so much for digital waveforms. You can see the warped signal in blue compared to what it should be in orange. To fix this, an op-amp comparator was used to clean up the signal, as well as boosting it to the required voltage.

Prefer your Arduino connections wireless? Check out this smartphone-controlled periodic table of elements, or this wireless robotic hand.

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Counting Bees With A Raspberry Pi

May 30, 2018 by 34 Comments

Even if keeping bees sounds about as wise to you as keeping velociraptors (we all know how that movie went), we have to acknowledge that they are a worthwhile thing to have around. We don’t personally want them around us of course, but we respect those who are willing to keep a hive on their property for the good of the environment. But as it turns out, there are more challenges to keeping bees than not getting stung: you’ve got to keep track of the things too.

Keeping an accurate record of how many bees are coming and going, and when, is a rather tricky problem. Apparently bees don’t like electromagnetic fields, and will flee if they detect them. So putting electronic measuring devices inside of the hive can be an issue. [Mat Kelcey] decided to try counting his bees with computer vision, and so far the results are very promising.

After some training, a Raspberry Pi with a camera can count how many bees are in a given image to within a few percent of the actual number. Getting an accurate count of his bees allows [Mat] to generate fascinating visualizations about his hive’s activity and health. With real-world threats such as colony collapse disorder, this type of hard data can be crucial.

This is a perfect example of a hack which might not pertain to many of us as-is, but still contains a wealth of information which could be applicable to other projects. [Mat] goes into a fantastic amount of detail about the different approaches he tried, what worked, what didn’t, and where he goes from here. So far the only problem he’s having is with the Raspberry Pi: it’s only able to run at one frame per second due to the computational requirements of identifying the bees. But he’s got some ideas to improve the situation.

As it so happens, we’ve covered a few other methods of counting bees in the past, though this is the first one to be entirely vision based. Interestingly, this method is similar to the project to track squirrels in the garden. Albeit without the automatic gun turret part.

Stock Market Prediction With Natural Language Machine Learning

May 30, 2018 by 38 Comments

Machines – is there anything they can’t learn? 20 years ago, the answer to that question would be very different. However, with modern processing power and deep learning tools, it seems that computers are getting quite nifty in the brainpower department. In that vein, a research group attempted to use machine learning tools to predict stock market performance, based on publicly available earnings documents. 

The team used the Azure Machine Learning Workbench to build their model, one of many tools now out in the marketplace for such work. To train their model, earnings releases were combined with stock price data before and after the announcements were made. Natural language processing was used to interpret the earnings releases, with steps taken to purify the input by removing stop words, punctuation, and other ephemera. The model then attempted to find a relationship between the language content of the releases and the following impact on the stock price.

Particularly interesting were the vocabulary issues the team faced throughout the development process. In many industries, there is a significant amount of jargon – that is, vocabulary that is highly specific to the topic in question. The team decided to work around this, by comparing stocks on an industry-by-industry basis. There’s little reason to be looking at phrases like “blood pressure medication” and “kidney stones” when you’re comparing stocks in the defence electronics industry, after all.

With a model built, the team put it to the test. Stocks were sorted into 3 bins —  low performing, middle performing, and high performing. Their most successful result was a 62% chance of predicting a low performing stock, well above the threshold for chance. This suggests that there’s plenty of scope for further improvement in this area. As with anything in the stock market space, expect development in this area to continue at a furious pace.

We’ve seen machine learning do great things before, too – even creative tasks, like naming tomatoes. 

The Tantillus, Reborn

May 30, 2018 by 34 Comments

In the beginning, around 2011 or thereabouts, there was an infinite variety of designs available for anyone to build their own 3D printer. There were Mendels, some weirdos were actually trying to build Darwins, and deltas were starting to become a thing. In the years since then, everyone just started buying cheap Prusa clones and wondering why their house burnt down.

One of the most innovative printers of this era was the Tantillus. It was a small printer, with the entire frame fitting in a 250mm square, but still able to print a 100mm cube. You could print the entire printer, and it was adorable. Face it: most of your prints aren’t bigger than 100mm unless you’re purposely printing something huge, and having a low moving mass is good.

The Tantillus has fallen by the wayside, but now it’s back. The Tantillus R — the ‘R’ means ‘reborn’ — is the latest project to take the design goals of the original Tantillus and bring it into the era of the modern RepRap ecosystem. (German, Google Translatrix, but the English translation of all the documentation is in the works),

Of note in this new design, the Tantillus R is still using shafts driven with high-test fishing line, driven by steppers and belts. The R version is getting away from the J-head, but in the interests in keeping the moving mass down, the hotend is a Merlin. This might seem an especially odd choice in the age of all-metal hotends, but again the goal is to keep moving mass down. As you would expect from a modern 3D printer, there’s support for a heated bed, you can plug a Raspberry Pi into it for Octoprint, and in true RepRap fashion, most of the parts are printable.

While the era of self-build 3D printers is probably over — you can’t compete with the cheap Chinese firestarters on price — the Tantillus R is a great project that retains the spirit of the RepRap projects while adding a few modern niceties and can still produce some impressive prints.

Convert A Curbside CRT TV Into An Arcade Monitor

May 30, 2018 by 29 Comments

While an old CRT TV may work well enough on a MAME cabinet project, the real arcade purists are quick to point out that a proper arcade monitor and a TV aren’t the same thing. A real arcade board uses RGB to connect to the monitor, that is, direct control over the red, green, and blue signals. Conversely video over coax or composite, what most people associate with old CRT TVs, combine all the video information down into an analog signal. Put simply, RGB allows for a much cleaner image than composite.

Many in the arcade restoration scene say that trying to convert a bog standard CRT TV into a RGB monitor isn’t possible, but [Arcade Jason] had his doubts. Over on his YouTube channel, he’s recently posted a tutorial on how to go from a trashed CRT TV to a monitor worthy of proper arcade gaming with relatively little work. As real arcade monitors are becoming increasingly rare, these kind of modifications are likely to get more common as coin-op gamers look to keep the old ways alive.

Now obviously every TV is going to do be different inside. All CRT TVs contain high voltages, and on some the circuit boards aren’t even mains-isolated, so take care if you try this. [Jason] certainly doesn’t claim that the method he demonstrates will work on whatever old TV you happen to have kicking around. But the general idea and some of the techniques he shows off are applicable to most modern TVs, and can help you tailor the method to your particular piece of gear. It all starts with a wet finger. Seriously.

[Jason] demonstrates a rather unique way of determining which pins on the TV’s control chip are responsible for the individual color signals by wetting his finger and sliding it over the pins. When a change in color is seen on the displayed image, you know you’re getting close. We can’t say it’s the most scientific or even the safest method, but it worked for him.

He then follows up with a jumper wire and resistor to find the precise pins which are responsible for each color, and solders up his actual RGB connection for the arcade board. In addition to the three color wires, a sync signal is also needed. This is the same sync signal used in composite video, so all that’s needed is to solder to the pad for the original composite video jack. Add a ground signal, and you’ve got yourself a proper RGB monitor.

Interestingly, this one has come full circle, as [Jason] says his attempt was inspired by an old post on Hackaday. It’s the Circle of Hacker Life.

[Thanks to Seebach for the tip]

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